High Transverse Thermoelectric Performance and Interfacial Stability of Co/Bi_0.5Sb_1.5Te₃ Artificially Tilted Multilayer Thermoelectric Devices

Artificially tilted multilayer thermoelectric devices (ATMTDs) have attracted extensive attention because of their numerous advantages, such as high integration, great structural freedom, and large transverse Seebeck coefficients. ATMTDs are composed of numerous alternating stackings of two types of materials with large differences in electrical and thermal transport. Therefore, it is of great interest to find ATMTDs with both high transverse thermoelectric performance and good interfacial stability to develop their practical application. In this work, cobalt (Co) and Bi0.5Sb1.5Te3 (BST) are chosen to prepare Co/BST ATMTDs. The interfacial structure and composition of Co/BST are characterized, and its interfacial stability and transverse thermoelectric performance are evaluated. The results show that the thickness of the Co/BST interfacial reaction layer is about 4 μm. Annealing at 473 K for 32 h does not increase the thickness, which indicates better interfacial stability than Ni/BST. After structure optimization, Co/BST ATMTD has ZTzx = 0.41, which is second only to YbAl3/BST ATMTDs. Meanwhile, the transverse Seebeck coefficient reaches −120.38 μV/K. The outstanding interfacial stability and transverse thermoelectric performance promise excellent thermal response and refrigeration performance with Co/BST ATMTDs.